1. Field of the Invention
The present invention relates to a non-volatile memory device and a memory system including the same.
2. Description of the Related Art
A flash memory device is a non-volatile memory device that retains stored data after power is turned off. Flash memory devices can be implemented a semiconductor memory devices capable of being electrically erased and programmed. Flash memory has been applied to mobile devices for executable code storage memories and as mass storage devices of mobile devices necessitate high-density and high-speed characteristics.
The flash memory devices may be classified as NAND flash memory devices or as NOR flash memory devices. A NOR flash memory device has a traditional memory cell structure having a plurality of memory cells connected in parallel to one bit line. By contrast, in a NAND flash memory device, a plurality of memory cells are connected in series with one bit line. The NOR flash memory device may perform program and read operation more rapidly than the NAND flash memory device. For this reason, the NOR flash memory devices have been widely used in applications that require rapid read/program speed.
But, the NOR flash memory device can be more difficult to miniaturize on a semiconductor chip with increasing storage capacity as compared with the NAND flash memory device. A multi level cell (MLC) storage system where plural data bits are stored in one physical memory cell has been adopted to increase the storage capacity without increasing chip size.